1. Field of the Invention
The present invention relates to a recording sheet using an oil ink for ink jet recording and in particular to an ink jet recording sheet excellent in the fixation and coloration of an oil ink containing a petroleum high-boiling point solvent.
2. Description of the Related Art
The ink jet recording system is a system where ink droplets are generated and scattered via ink nozzles of an ink jet printer and allowed to adhere to the surface of a recording material, thus forming an graphic recorded thereon. Because of high-speed printing, easy multi-colored printing, suitability for recording a large graphic, silent sound at the time of recording, low running costs etc., the ink jet recording system has attracted particular attention in recent years, and new techniques therefor have extensively been developed.
In development of techniques in this recording system, the ink itself has been developed along with, or independently of, the development of the apparatus with respect to the structure, mechanism etc. of the ink jet printer, and further a recording material suitable for the used ink has been intensively developed.
In respect of the ink, an aqueous ink has been developed preferentially over an oil ink because of often occurring clogging in a nozzle caused by drying in the printer, and a recording material has been developed preferentially for this aqueous ink.
However, an oil ink excellent in characteristics such as dispersion of pigments has been developed recently and simultaneously a printer apparatus suitable for such oil ink has been developed, so the problem of clogging of nozzles described above is now being solved, and therefore particular attention is paid recently to the ink jet recording system using the oil ink.
The recording system using the oil ink has attracted attention for the above reasons and further because a record graphic formed on an ink receiving layer in a recording material is inherently superior in water resistance, thus making it usable as a paper used outdoors, such as poster, billboard and label without particularly subjecting it to water resistance treatment etc.
Because no recording material with superior performance has been developed and provided for the ink jet recording system using the oil ink, a recording material for the aqueous ink is now used.
Such recording materials include an ink jet recording sheet comprising a substrate poor in water absorption provided thereon with a water-soluble polymeric coating layer as an ink jet recording sheet (Japanese Laid-Open Patent Publication No. 146786/1980), a recording sheet comprising a water-non-absorptive substrate provided with an anchor coat layer based on an aqueous copolymer polyester (Japanese Laid-Open Patent Publication No. 46289/1985), and a recording material comprising a substrate provided with an ink-receiving layer via an anchor coat layer insoluble in water-soluble organic solvent (Japanese Laid-Open Patent Publication No. 134285/1987).
However, any recording materials or sheets described above have been developed for the aqueous ink, so if the oil ink is used for recording, absorption of the ink solvent is inferior, thus causing problems such as inadequate printing by flowing of printed graphics.
Further, how the ink solvent is to be treated by absorption etc. in a recording material or a recording sheet is very closely related to ink fixation and coloration in the case of the oil ink as compared with the aqueous ink, but there is no proposal for the recording material and recording sheet to solve such problems.